关于GNRMC解析
JT808格式
关键代码C语言
#include "stdafx.h"
#include "stdafx.h"
#include <string.h>
#include <stdlib.h>
#include <stdio.h>
struct GNRMC_Info
{
unsigned int year;
unsigned char month;
unsigned char day;
unsigned char hour;
unsigned char Minute;
unsigned char second;
unsigned int longitude;
unsigned char longitude_suffix; // E或W
unsigned int latitude;
unsigned char latitude_suffix;
unsigned char position_valid; // 有效
};
struct China_Time
{
unsigned int year;
unsigned char month;
unsigned char day;
unsigned char hour;
unsigned char Minute;
unsigned char second;
};
struct China_Time Ch_TM;
int comma_split(unsigned char *pstr, char *buf, int buflen, int s, int e)
{
int i, k;
int commaCount = 0;
int rc = -1;
i = k = 0;
if (e <= s)
{
return -1;
}
while (pstr[i] != '\0')
{
if (pstr[i] == ',')
{
commaCount++;
}
if (commaCount == s)
{
k = ++i;
break;
}
i++;
}
while (pstr[i] != '\0')
{
if (pstr[i] == ',')
{
commaCount++;
}
if (commaCount == e)
{
if (i - k + 1 > buflen)
{
return -1;
}
memset(buf, 0, sizeof(buf));
memcpy(buf, pstr + k, i - k);
rc = i - k;
buf[rc] = '\0';
//printf("%s\n", buf);
break;
}
i++;
}
return rc;
}
int GNRMC_Parse(unsigned char *pstr, struct GNRMC_Info *pGNRMCInfo)
{
int len = 0;
int commaCount = 0;
double temp = 0;
char buf[32] = {0};
// 计算字符串长度
while (pstr[len] != '\0')
{
if (pstr[len] == ',')
{
commaCount++;
}
len++;
}
// 逗号个数是12个
if (commaCount != 12)
{
return -1;
}
// 判断开始字符是:$GNRMC
if (!((pstr[0] == '$') && (pstr[1] == 'G') && (pstr[2] == 'N') && (pstr[3] == 'R') && (pstr[4] == 'M') && (pstr[5] == 'C')))
{
return -1;
}
// 判断结束字符是:\r\n
if ((pstr[len - 2] != '\r') && (pstr[len - 1] != '\n'))
{
return -1;
}
// UTC时间:第1个逗号与第2个逗号之前 (eg:092846.400 hhmmss.sss )
len = comma_split(pstr, buf, sizeof(buf), 1, 2);
if (len < 0)
{
return -1;
}
pGNRMCInfo->hour = (buf[0] - '0') * 10 + (buf[1] - '0');
pGNRMCInfo->Minute = (buf[2] - '0') * 10 + (buf[3] - '0');
pGNRMCInfo->second = (buf[4] - '0') * 10 + (buf[5] - '0');
// 定位状态:第2个逗号与第3个逗号之前
len = comma_split(pstr, buf, sizeof(buf), 2, 3);
if (len != 1)
{
return -1;
}
pGNRMCInfo->position_valid = ((buf[0] == 'A') ? 1 : 0);
// 经度
len = comma_split(pstr, buf, sizeof(buf), 3, 4);
if (len < 0)
{
return -1;
}
temp = atof(buf);
temp = temp * 10000;
pGNRMCInfo->longitude = temp;
// 经度半球E(东经)或W(西经)
len = comma_split(pstr, buf, sizeof(buf), 4, 5);
if (len != 1)
{
return -1;
}
pGNRMCInfo->longitude_suffix = buf[0];
// 纬度
len = comma_split(pstr, buf, sizeof(buf), 5, 6);
if (len < 0)
{
return -1;
}
temp = atof(buf);
temp = temp * 10000;
pGNRMCInfo->latitude = temp;
// 纬度半球N(北半球)或S(南半球)
len = comma_split(pstr, buf, sizeof(buf), 6, 7);
if (len != 1)
{
return -1;
}
pGNRMCInfo->latitude_suffix = buf[0];
// UTC日期:ddmmyy(日月年)格式 eg:070417
len = comma_split(pstr, buf, sizeof(buf), 9, 10);
if (len < 0)
{
return -1;
}
pGNRMCInfo->day = (buf[0] - '0') * 10 + (buf[1] - '0');
pGNRMCInfo->month = (buf[2] - '0') * 10 + (buf[3] - '0');
pGNRMCInfo->year = (buf[4] - '0') * 10 + (buf[5] - '0') + 2000;
return 0;
}
void UTCToChina(unsigned int UTCYear,unsigned char UTCMonth,unsigned char UTCDay,unsigned char UTCHour,unsigned char UTCMinutes,unsigned char UTCSeconds)
{
unsigned int ChinaYear = UTCYear;
unsigned char ChinaMonth = UTCMonth;
unsigned char ChinaDay = UTCDay;
unsigned char ChinaSeconds = UTCSeconds;
unsigned char ChinaMinutes = UTCMinutes;
unsigned char ChinaHour = UTCHour + 8;
if (ChinaHour > 23)
{
ChinaHour -= 24;
ChinaDay++;
switch (ChinaMonth)
{
case 1:
if (ChinaDay > 31)
{
ChinaDay = 1;
ChinaMonth++;
}
break;
case 2:
if ((0 == ChinaYear % 4 && 0 != ChinaYear % 100) || 0 == ChinaYear % 400)
{
if (ChinaDay > 29)
{
ChinaDay = 1;
ChinaMonth++;
}
}
else
{
if (ChinaDay > 28)
{
ChinaDay = 1;
ChinaMonth++;
}
}
break;
case 3:
if (ChinaDay > 31)
{
ChinaDay = 1;
ChinaMonth++;
}
break;
case 4:
if (ChinaDay > 30)
{
ChinaDay = 1;
ChinaMonth++;
}
break;
case 5:
if (ChinaDay > 31)
{
ChinaDay = 1;
ChinaMonth++;
}
break;
case 6:
if (ChinaDay > 30)
{
ChinaDay = 1;
ChinaMonth++;
}
break;
case 7:
if (ChinaDay > 31)
{
ChinaDay = 1;
ChinaMonth++;
}
break;
case 8:
if (ChinaDay > 31)
{
ChinaDay = 1;
ChinaMonth++;
}
break;
case 9:
if (ChinaDay > 30)
{
ChinaDay = 1;
ChinaMonth++;
}
break;
case 10:
if (ChinaDay > 31)
{
ChinaDay = 1;
ChinaMonth++;
}
break;
case 11:
if (ChinaDay > 30)
{
ChinaDay = 1;
ChinaMonth++;
}
break;
case 12:
if (ChinaDay > 31)
{
ChinaDay = 1;
ChinaMonth = 1;
ChinaYear++;
}
break;
default:
break;
}
}
Ch_TM.year=ChinaYear;
Ch_TM.month=ChinaMonth;
Ch_TM.day=ChinaDay;
Ch_TM.hour=ChinaHour;
Ch_TM.Minute=ChinaMinutes;
Ch_TM.second=ChinaSeconds;
}
/*for( int i = 0; i < 4; i++ )//这部分为发送数组赋值，整形拆分为4个字节
{
sy[ i ] = (char)(GNRMC.longitude >> ( 24 - i*8 ));
}*/
char buff[]={'$','G','N','R','M','C',',','1','3','2','2','2','2','.','0','0','0',',','A',',',
'3','1','0','3','.','8','9','6','6',',','N',',','1','2','1','1','8','.','3','5','7',
'1',',','E',',','1','.','6','9',',','3','2','2','.','3','9',',','1','3','0','2','1','9',
',',',',',','A','*','7','6','\r','\n'};//Test
int main(int argc, char* argv[])
{
struct GNRMC_Info GNRMC;
char* p= "$GNRMC,132222.000,A,3103.8966,N,12118.3571,E,1.69,322.39,130219,,,A*76\r\n";
GNRMC_Parse((unsigned char *)p,&GNRMC);
UTCToChina(GNRMC.year,GNRMC.month,GNRMC.day,GNRMC.hour,GNRMC.Minute,GNRMC.second);
printf("时间:%d-%d-%d %d:%d:%d\n",Ch_TM.year,Ch_TM.month,Ch_TM.day,Ch_TM.hour,Ch_TM.Minute,Ch_TM.second);
printf("%u %c ---- %u %c 定位是否有效果:%d\n",GNRMC.longitude,GNRMC.longitude_suffix,GNRMC.latitude,GNRMC.latitude_suffix,GNRMC.position_valid);
getchar();
return 0;
}
关于初始化部分：
GPS_Info数组初始化ID，经纬度，和时间值。目前没有添加高度和速度。
unsigned char GPS_Info[49]={' '};
unsigned char Mac_Id[6]={0x01,0x60,0x20,0x85,0x00,0x00};//16020850000
void GPS_Info_Init()
{
for(int i=0;i<49;i++)
{
GPS_Info[i]=0x00;
}
GPS_Info[0]=GPS_Info[48]=0x7e;
GPS_Info[1]=0x02;
GPS_Info[4]=0x22;//消息体属性
for(int n=0;n<6;n++)
{
GPS_Info[n+5]=Mac_Id[n];
}
}
void Longti_Lati_Set()//这部分为收到GPS数据后格式化到GPS_Info数组
{
unsigned char result=0x00;
unsigned char bcd_year=0x00;
unsigned char bcd_month=0x00;
unsigned char bcd_day=0x00;
unsigned char bcd_hour=0x00;
unsigned char bcd_Minute=0x00;
unsigned char bcd_second=0x00;
for(int n=0;n<4;n++)
{
GPS_Info[n+21]=(char)(GNRMC.longitude >> ( 24 - n*8 ));
GPS_Info[n+25]=(char)(GNRMC.latitude >> ( 24 - n*8 ));
}
bcd_year=(Ch_TM.year/10*16)+(Ch_TM.year%10);
bcd_month=(Ch_TM.month/10*16)+(Ch_TM.month%10);
bcd_day=(Ch_TM.day/10*16)+(Ch_TM.day%10);
bcd_hour=(Ch_TM.hour/10*16)+(Ch_TM.hour%10);
bcd_Minute=(Ch_TM.Minute/10*16)+(Ch_TM.Minute%10);
bcd_second=(Ch_TM.second/10*16)+(Ch_TM.second%10);
GPS_Info[35]=bcd_year;
GPS_Info[36]=bcd_month;
GPS_Info[37]=bcd_day;
GPS_Info[38]=bcd_hour;
GPS_Info[39]=bcd_Minute;
GPS_Info[40]=bcd_second;
result=GPS_Info[1];//校验码
for(int i=2;i<=46;i++)
{
result^=GPS_Info[i];
}
GPS_Info[47]=result;
}
校验码指从消息头开始，同后一字节异或，直到校验码前一个字节，占用一个字节。
关于校验码函数，此函数无需添加到工程，只作为测试
unsigned char verification()//取得校验码
{
unsigned char result=0x00;
unsigned char spk[]={0x7E, 0x02 ,0x00, 0x00, 0x22, 0x54, 0x40, 0x71 ,0x46 ,0x06 ,0x70, 0x00, 0x3E, 00 ,00, 00, 00, 00, 00, 00, 02, 01, 0x58 ,
0xE2, 0xB4, 0x06, 0xC9, 0xAD, 0xE7, 00, 0x20, 00, 00, 00, 0x5D, 0x18, 0x09, 0x27, 0x10, 0x35, 0x12, 0x01, 0x04, 00, 00, 00, 00, 0xBA, 0x7E};
result=GPS_Info[1];//校验码
for(int i=2;i<=46;i++)
{
result^=spk[i];
}
return result;
}